Amide-containing self-emulsifying epoxy curing agent

ABSTRACT

A new epoxy hardener composition is the product of the reaction of (A) a poly(alkylene oxide) monoamine or diamine with a molecular weight (Mn) of about 500 to 3000 and (B) a di- or polycarboxylic acid, in a ratio of moles of carboxylic acid to equivalents of amine of about 1:1 to 6:1 to yield an intermediate (C), which in a second step is reacted with (D) a di- or polyamine. The compositions of the invention are excellent emulsifiers of liquid epoxy resins in aqueous media without the addition of added surfactants or acidic compounds, and can be used to prepare water resistant water-borne coatings and related products from both liquid and solid epoxy resins, that possess long pot lives and contain relatively small amounts of volatile organic compounds.

This is a division of application Ser. No. 08/355,149 filed 13 Dec.1994.

TECHNICAL FIELD

This invention relates to water dispersible polyamine-epoxy adductswhich can be used as a curative for both liquid and solid epoxy resinsystems.

BACKGROUND OF THE INVENTION

Coatings based on a combination of epoxy resins and amine hardeners(curing agents) which react to form a crosslinked film have enjoyedwidespread use for decades. Because of the combination of propertiesachievable they have developed strong market positions in thoseapplications where a high degree of resistance to water, chemicalreagents, or corrosive environments is required.

A good introduction to the general chemistry of epoxy resins isavailable in H. Lee and K. Neville, `Handbook of Epoxy Resins" (1967,McGraw -Hill Inc.). Commercially available epoxy resins useful incoatings are frequently referred to as either liquid resin or solidresin. The commercially important solid epoxy resins have an epoxyequivalent weight (EEW) greater than about 450. Although much higher EEWepoxy resins are available, the resins employed in amine cured coatingsgenerally have an EEW less than about 1000. At higher equivalent weightsthe resulting crosslink density is too low to give the desiredproperties. Commercially important liquid epoxy resins have an EEW ofless than about 250, and more frequently less than about 200. Thoughmuch slower to dry than solid epoxies, they result in films with veryhigh crosslink densities, and find utility where very chemicallyresistant coatings are required. Of course, they also require lesssolvent for application than traditional solvent borne formulations.There is also a class of epoxy resins sometimes referred to assemi-solid resins, with EEWs intermediate between liquid and solid. Itshould be realized that a reference to `liquid` or `solid` resin mayrefer not to the actual physical state of the resin, but to the resin'sEEW range, and perhaps to the properties that may be anticipated withits use. Thus, an aqueous dispersion of an epoxy resin with an EEW of500 may be referred to as a solid resin dispersion, even though it is ina liquid form.

Concerns over environmental pollution and the health risks associatedwith chemical exposure have resulted in an intense effort by coatingsmanufacturers and raw material suppliers to develop products that havelower volatile organic content (VOC). Solvents are required in coatingsto, among other things, allow the inherently viscous materials whichcomprise the coating formulation to be applied in a manner that resultsin a continuous thin film that will harden or cure with the requiredappearance and physical properties. No single approach to reducing thesolvent content in two component epoxy coatings has been found whichresults in a product with the high degree of performance in differentapplications that typify the traditional, high VOC products.

One method of lowering VOC is to replace some of the solvent with water.This approach has not been without drawbacks. They include an increasedsensitivity of water-borne epoxies to water and corrosive environments,and relatively short pot lives.

It will also be appreciated by those skilled in the art that replacing asubstantial amount of solvent with water does not result in a truesolution of the film forming components of an epoxy coating. To preventphase separation and maintain a dispersed state of colloidal dimensions,it is necessary to impart an energy barrier to the agglomeration of thecolloidal particles. There are two generally recognized means toaccomplish this. The first is to surround the particles withelectrically charged species of like sign. In water-borne epoxy coatingsit is possible to incorporate charged species with the use of ionicsurfactants, but more commonly this is accomplished by adding a compoundof sufficient acidity to react with the amine to form a substantialequilibrium concentration of alkyl ammonium ion. Acids such as aceticacid and the like are frequently employed. Such an approach is employedin U.S. Pat. No. 4,246,148; U.S. Pat. No. 4,539,347; U.S. Pat. No.4,608,405 and U.S. Pat. No. 5,246,984. Adding acids such as acetic acidor increasing their use level in some cases can also enhance the potlife of a water-borne epoxy, probably either by slowing the overall rateof the amine/epoxy reaction, or by imparting additional colloidalstability. In some cases, the ammonium containing curing agent iscombined with already emulsified epoxy resins such as those describedbelow, or in some cases the ammonium containing curing agent is used todirectly emulsify the epoxy resin. Unfortunately, water-borne epoxycoatings made by this approach do not have the same degree of water andcorrosion resistance of traditional epoxy coatings. Also, systems thatrely on the ammonium containing curing agent as the primary emulsifierof the epoxy resin tend to suffer from quite short pot lives.

The other general method of imparting colloidal stability in an aqueousenvironment is to surround the particles with polymeric chains, such aspolyethylene oxide chains, which have a high degree of water solubility.One way of practicing this method of stabilization is to add aconventional nonionic surfactant to the epoxy resin. There arecommercially available products that consist of a pre-emulsifiedcombination of low molecular weight (liquid) epoxy resin and nonionicsurfactant, or a similar combination which is emulsified by the resinuser. Sometimes, special block copolymer surfactants are employed thatare designed to have one block highly compatible with the epoxy resinemployed, such as described in U.S. Pat. No. 4,446,256.

A different method for nonionic stabilization can be employed asdisclosed in U.S. Pat. No. 4,315,044 and U.S. Pat. No. 4,608,406. Thediglycidyl ether of a poly(alkylene oxide) diol is incorporated in theepoxy resin advancement of a diphenol and a di- or polyglycidyl ether.In this way, water soluble chains become chemically attached to theadvanced, solid epoxy resin, which is then converted into an aqueousdispersion by the addition of water and co-solvents and the applicationof shear.

Also known in the art are water-borne poly(alkylene oxide) epoxyhardeners with chemically attached nonionic emulsifying chains. Ahardening agent for an aqueous epoxy resin composition comprising areaction product of (a) at least one polyepoxide compound, (b) at leastone polyalkylene polyether polyol and (c) at least one compound selectedfrom the group consisting of aliphatic, cycloaliphatic, and heterocyclicpolyamines is described in U.S. Pat. No. 4,197,389.

A curing agent for epoxy resins showing good water compatibility isdescribed in DE 4,206,392. It consists of (A) polyamidoamines obtainedby polycondensation of (a) dicarboxylic acids that contain oxyalkylenegroups or their derivatives with (b) polyamines that contain at leasttwo amino groups condensable with (a), (B) polyamines with at least twosecondary amino groups and (C) adducts from (c) polyepoxide compoundsand (d) polyalkylene polyether polyols.

Water-borne epoxy curing agents which are essentially adducts ofdiglycidyl ethers of polyethers with polyamines are described in GB1,326,435. Exemplary amines are the polyethylene amines.

U.S. Pat. No. 5,032,629 describes a hardening agent for epoxy resinswhich is prepared in two steps. In the first step at least one member ofthe group consisting of polyalkylene polyether monoamines and diaminesand polyamines with a mean molecular weight of 148 to 5000 is reactedwith at least one member of the group consisting of diepoxy compoundsand polyepoxy compounds in a ratio of hydrogen atoms bound to nitrogenand capable of reaction with epoxide to epoxides of di- or polyepoxycompounds of 1:1.4 to 6. In the second step, at least one member of thegroup consisting of primary and secondary aliphatic, araliphatic,cycloaliphatic, aromatic, and heterocyclic mono-, di- and polyamines isreacted with the product of the first step at a ratio of reactiveepoxide groups to hydrogen atoms on nitrogen of 1:2 to 10.

Perhaps most relevant to the present invention is DE 2,519,390 whichdiscloses a water-borne polyamide curing agent which is made by reactinga polycarboxylic acid with polyamines. At least 10 mole % of thepolyamines are poly(alkylene oxide) amines. According to calculations,Example 5 shows all the components being reacted together in a 0.95:1ratio of moles of diacid to equivalents of polyether amine nitrogen.

SUMMARY OF THE INVENTION

The present invention provides a water compatible poly(alkyleneoxide)amide composition and curable coating compositions comprising ablend of such poly(alkylene oxide)amide composition and a polyepoxide.

The poly(alkylene oxide)amide composition comprises the reaction productof (A) a poly(alkylene oxide) mono- or diamine having a number averagemolecular weight (Mn) of 500 to 3000 and (B) a polycarboxylic acid in aratio of moles of polycarboxylic acid to equivalents of amine of about1:1 to 6:1 to yield an intermediate (C) which is reacted with (D) apolyamine. The amount of the poly(alkylene oxide) monoamine or diamineused to produce intermediate (C) should be sufficient to provide astable solution or emulsion of the epoxy hardener composition in anaqueous medium, i.e., in water or a water-cosolvent mixture.

This resulting polyamide reaction product is readily dispersible in theaqueous media and is capable of dispersing liquid and solid polyepoxideresins in such aqueous media. Thus, another embodiment of the presentinvention is a curable coating composition comprising the poly(alkyleneoxide)amide composition and a polyepoxide resin.

The compositions of this process are similar to those of DE 2,519,390except that the poly(alkylene oxide) amine is reacted with excesspolycarboxylic acid in a first step and then with a large excess ofpolyamine in a second step. In this manner, the poly(alkylene oxide)amine is completely or nearly completely covalently attached to thepolycarboxylic acid and eventually to the hardener and the final filmnetwork. Water sensitivity from the poly(alkylene oxide) chain should beminimized and all of the poly(alkylene oxide) chains in the hardenerwill be part of an amphophilic molecule, and hence surface active.

The poly(alkylene oxide)amides are excellent emulsifiers of liquidpolyepoxide resins in aqueous media without the addition of addedsurfactants or acidic compounds and can be used to prepare waterresistant water-borne coatings and related products from both liquid andsolid polyepoxide resins that possess long pot lives and containrelatively small amounts of VOC.

DETAILED DESCRIPTION OF THE INVENTION

According to the invention the poly(alkylene oxide)amide compositioncomprises the reaction product of (A) a poly(alkylene oxide) monoamineor diamine having a number average molecular weight (Mn) of 500 to 3000and (B) a polycarboxylic acid in a ratio of moles of polycarboxylic acidto equivalents of amine of about 1:1, preferably 1.3:1, to 6:1 to yieldan intermediate (C). The amount of poly(alkylene oxide) monoamine ordiamine used in producing intermediate (C) represents that amountsufficient to afford stable solutions or emulsions of the final curingagent in an aqueous medium, and to afford an emulsion of the curingagent and epoxy resin in an aqueous medium with sufficient stability tobe a useful coating vehicle, e.g., 15 to 40 wt %, preferably 18 to 25 wt%, of the final hardener composition solids. In a second stepintermediate (C) is reacted with (D) a polyamine in an amount thatensures the requisite amount of poly(alkylene oxide) amine in the finalcomposition.

The poly(alkylene oxide) amines used in the first step comprisepoly(alkylene oxide) chains that are terminated on one end or on bothends with amine groups, monoamines and diamines, respectively. It isnecessary that the amine groups have at least one active hydrogen; i.e.,they must be 1° or 2° amines. The monoamines are preferred to thediamines, because at equivalent molecular weights, their use shouldresult in lower viscosity hardeners, and because it is believed that themonofunctional chains are more effective stabilizers at equal molecularweight. The poly(alkylene oxide) can be derived from ethylene oxide,propylene oxide, or butylene oxide, or mixtures of the above either inrandom or block copolymer forms. However, it is necessary that thepoly(alkylene oxide) chains, or at least suitably long sections of thesechains to act as steric stabilizers, be soluble in the continuous phasemedium of the final coating formulation. Thus, as the VOC of the finalformulation is reduced by elimination of cosolvent, it will be necessaryto raise the level of ethylene oxide in the copolymer, since it is theonly poly(alkylene oxide) that is completely water soluble at thenecessary molecular weights. The number average molecular weight (Mn) ofthe poly(alkylene oxide) amine is about 500 to about 3000, preferablyabout 800 to about 1500. Lower molecular weights result in colloidalinstability, while higher molecular weights increase viscosity of theproduct and require lower solids in the final formulation.

Specific examples of suitable monoamines are the Jeffamine® M-600,Jeffamine M-1000, Jeffamine M-2005, and Jeffamine M-2070 amines.Specific examples of suitable diamines are Jeffamine D-2000, JeffamineED-600, Jeffamine ED-900, and Jeffamine ED-2001 amines. The Jeffaminematerials are commercially available from the Huntsman Corp. Thepreferred monoamine is Jeffamine M-1000 amine which is a monoamineterminated block copolymer of propylene oxide and ethylene oxide havingan Mn=1200, based on its amine titer.

The poly(alkylene oxide) amine can range from about 15% to about 40% ofthe final hardener composition (based on solids). If too littlepoly(alkylene oxide) amine is employed, the hardener has insufficientsolubility in the continuous phase of the formulation, resulting ininadequate pot life and stability. At high levels, water resistance ofthe derived coatings will be adversely affected. The preferred .range isabout 18% to about 25%.

The polycarboxylic acid of the first step can be any carboxylic acidcontaining two or more carboxylate functionalities and from about 3 toabout 40 carbons; however, the dicarboxylic acids are much preferred.Functional equivalents of dicarboxylic acids for purposes of thisinvention include ester derivatives of the dicarboxylic acids or anyother derivative that can react with an amine to form an amide,providing that other products of the reaction can either be removed, ordo not harm the properties of the final product. Anhydrides of thedicarboxylic acid can also be employed. Mixtures of dicarboxylic acidscan also be employed.

Specific examples of suitable dicarboxylic acids containing 3 to 12carbon atoms include the saturated dicarboxylic acids such as malonicacid, succinnic acid, glutaric acid, adipic acid, azeleic acid,1,8-octanedicarboxylic acid, 1,10-decanedicarboxylic acid,1,12-dodecanedicarboxylic acid, and the like, as well as alkylsubstituted derivatives of the above and specific examples of suitablearomatic dicarboxylic acids include phthalic acid, isophthalic acid, andterephthalic acid.

Unsaturated dicarboxylic acids can also be employed, including dimeracids. The dimer acids are prepared by dimerization of fatty acids suchas tall oil fatty acid and the like. They are complex mixtures that alsoinclude some monofunctional and higher functional carboxylic acids. Itshould be recognized that the average functionality of such a mixturemay not be exactly 2. However, average functionality far less than twowill result in the formation of a large amount of the amide ofmonofunctional acid and poly(alkylene oxide) amine. This product willnot be reacted into the final crosslinked network, and its presence inlarge amounts would be expected to reduce water resistance. Use ofpolycarboxylic acids with a functionality much greater than 2 would beexpected to increase the viscosity of the hardener to an unacceptabledegree due to chain branching on reaction with amine in the second stepalthough their use in small amounts may be acceptable, especially incombination with a dicarboxylic acid. The dimer acids are well known inthe literature, and well described in DE 2,519,390.

In the following examples, the compositions are all based on a dimerfatty acid. In practice that results in a product that yields a veryflexible coating, but also one that is fairly slow to cure. This isprobably a result of the low Tg imparted to the system through theincorporation of dimer acid. In cases where a faster drying coating isrequired, it would be preferred to use one or more of the lowermolecular weight diacids given above perhaps in mixture with a dimeracid. The preferred diacids would be those containing 3 to 12 carbonatoms such as malonic acid, succinnic acid, glutaric acid, adipic acid,azeleic acid, 1,8-octanedicarboxylic acid, 1,10-decanedicarboxylic acid,1,12-dodecanedicarboxylic acid, phthalic acid, isophthalic acid, andterephthalic acid. If greater flexibility is required in the finalcoating, it would prove possible to improve it by including a flexiblediamine such as Jeffamine D400 or D2000 in the B side of the finalformulation.

The ratio of moles of polycarboxylic acid to equivalents of amine in thefirst step of the process should be kept high enough so that not toomany polyamides are formed that have two or more polyether chainsattached to a single di- or multifunctional carboxylic acid, which wouldbe expected to reduce water resistance. It should be kept low enough sothat the required level of poly(alkylene oxide) is incorporated into thecomposition while ensuring that the viscosity of the final product islow enough to produce workable compositions below the required VOC sinceexcess carboxylic acid serves to polymerize the amines of the secondstep. It will be apparent to those skilled in the art that the secondrequirement is dependent upon the functionality of the components in thereaction, since the reaction of materials of high functionality leads tohigher molecular weights than lower functionality materials at the samemolar ratios. Accordingly, the ratio of moles of polycarboxylic acid toequivalents of amine should be about 1:1 to 6:1, with the preferredrange being about 1.3:1 to about 2.6:1. It is clear that by specifyingthe total percent of poly(alkylene oxide) amine in the composition, andthe ratio of poly(alkylene oxide) amine to dicarboxylic acid, that thetotal composition is fixed.

Polyamines useful in the second step contain at least two nitrogen atomsper molecule and at least two and preferably at least three activehydrogens attached to nitrogen atoms per molecule. Useful amines includealiphatic, araliphatic, aromatic, cycloaliphatic, and heterocyclic di-and polyamines. Examples include the polyethylene amines (ethylenediamine, diethylene triamine, triethylene tetramine, pentaethylenehexamine and the like), 1,2-propylene diamine, 1,3-propylene diamine,1,4-butanediamine, 1,5-pentanediamine, 1,3-pentanediamine,1,6-hexanediamine, 3,3,5-trimethyl-1,6-hexanediamine,3,5,5-trimethyl-1,6-hexanediamine, 2-methyl-1,5-pentanediamine,bis-(3-aminopropyl)amine, N,N'-bis-(3-aminopropyl)-l,2-ethanediamine,N-(3-aminopropyl)-1,2-ethanediamine, 1,2-diaminocyclohexane,1,3-diaminocyclohexane, 1,4-diaminocyclohexane, aminoethylpiperazine,the poly(alkylene oxide) diamines and triamines (such as for exampleJeffamine®D-230, Jeffamine D-400, Jeffamine D-2000, Jeffamine D-4000,Jeffamine To403, Jeffamine EDR-148, Jeffamine EDR-192, Jeffamine C-346,Jeffamine ED-600, Jeffamine ED-900, and Jeffamine ED-2001 ),meta-xylylene diamine, phenylene diamine, 4,4'-diaminodiphenyl methane,toluene diamine, isophorone diamine,3,3'-dimethyl-4,4'-diaminodicyclohexyl methane, 4,4'-diaminodicyclohexylmethane, 2,4'-diaminodicyclohexyl methane, the mixture of methylenebridged poly(cyclohexyl-aromatic)amines (also known as MBPCAA) describedin U.S. Pat. No. 5,280,091, and polyaminoamides. Mixtures of the aboveamines may also be employed.

The preferred amines for use in the invention are4,4'-diaminodicyclohexyl methane, and particularly the mixture ofmethylene bridged poly(cyclohexyl-aromatic)amines described in U.S. Pat.No. 5,280,091.

If desired, the amine hydrogen functionality of the first or secondamine component or their combined product can be reduced in order tofurther improve pot life by reducing the reactivity of the amine orenhancing the compatibility of the curing agent with the epoxy resin.This can be accomplished in several ways well known to those skilled inthe art. The first method is to react a portion of the amine hydrogenwith a monoepoxide. Examples of useful monoepoxides include styreneoxide, cyclohexene oxide, ethylene oxide, propylene oxide, butyleneoxide, and the glycidyl ethers of phenol, the cresols, tert-butylphenoland other alkyl phenols, butanol, and 2-ethylhexanol and the like. Thesecond method is to react a portion of the amines with an aidehydecontaining about 1-8 carbons, such as formaldehyde, butyraldeyde,benzaldehyde, and the like. A third method is to condense a portion ofthe amines with a monocarboxylic acid having from 1 to about 18 carbonssuch as acetic acid, benzoic acid, or one of the fatty acids such asstearic acid or oleic acid. A fourth method is to react a portion of theamines with an unsaturated compound that contains an electronwithdrawing group that activates the double bond to undergo the Michaelreaction with an amine. Examples of useful unsaturated compounds of thistype include acrylonitrile, acrylamide, N-methylol acrylamide, and thelike.

The ratio of equivalents of amine to equivalents of carboxylate in thefinal step must be kept high enough so that the molecular weight of theproduct is not built up to too great an extent, causing a too highviscosity. However, it must be kept low enough to achieve the desiredlevel of poly(alkylene oxide) amine content in the hardener. It will beapparent to those skilled in the art that the first requirement isdependent upon the functionality of the components in the reaction,since the reaction of materials of high functionality leads to highermolecular weights than lower functionality materials at the same molarratios. The minimum ratio of equivalents of amine to moles of carboxylicacid is about 5, with the preferred minimum ratio being about 15.

If desired, additional polyamine, the same or different, may be blendedinto the hardener composition after the second reaction is complete.

Also contemplated as the functional equivalent to the second step ofreacting the total amount of polyamine with the carboxylate-containingintermediate (C), is to divide the total polyamine amount into twoportions, the first being an amount sufficient to provide a ratio ofequivalents of amine to moles of carboxylic acid of at least about 5.This first portion is reacted in the second step with thecarboxylate-containing intermediate (C) followed by the addition of theremaining, or second portion, of the polyamine to the hardenercomposition after the second reaction is complete.

Normally, to blend additional polyamine into the product of the secondreaction would result in a higher viscosity product than would beobtained if all of the polyamine were present when thecarboxylate-containing intermediate is added. However, it will berecognized by those skilled in the art that the difference will beslight as long as a large molar excess of amine to epoxy is present inthe first portion.

Furthermore, it is possible to impart certain desirable properties tothe final coating by blending in amines that have different propertiesthan the amine used in the reaction with the polycarboxylic acid andpoly(alkylene oxide) amine reaction product. For example, theflexibility and impact resistance of the coating can be improved byblending in a portion of Jeffamine D400 or D2000 amine. When blending inadditional amines, it is important that the final level of poly(alkyleneoxide) amine in the resulting product be sufficient to impart thenecessary stability to the system as described above.

Both reactions in the preparation of the hardener can be conducted overa wide temperature range, from about 100° C. to 300° C., with thepreferred temperature about 180° C. to 260° C. The temperature requiredwill usually be determined by the temperature necessary to remove waterfrom the reaction mixture. By the application of vacuum, the requiredtemperature can be reduced substantially below the temperatures employedin the example.

Another method to reduce the reaction temperature is to substituteesters derived from the dicarboxylic acids and alcohols containing from1 to about 6 carbon atoms for the dicarboxylic acids. The products ofsuch a substitution are the same amides plus the alcohol. The alcoholcan either be removed from the reaction mixture by distillation atatmospheric or reduced pressure, or it can be left in if its presence isacceptable in the final formulation.

To minimize viscosity of the final product, it is preferred to add thepoly(alkylene oxide) amine to the carboxylic acid in the first step, andto add the resulting intermediate to the polyamine in the second step.It will frequently be desirable to dilute the final product with asolvent so that the final product will be in a more convenient, lessviscous form. The best solvents are solvents that are useful in theformulation of the final coating, such as those described below. Thepreferred solvents are the glycol ethers described below, and the mostpreferred solvent is ethylene glycol monopropyl ether (EP).

The curing agents, or hardeners, of this invention are useful inapplications requiring a relatively thin film of cured epoxy resin, suchas coatings and adhesives. They are used to cure resins or mixtures ofresins containing 1,2-epoxy groups. The epoxy resins or epoxy resinmixture may be liquid or solid in nature, and have an epoxide equivalentweight (EEW) based on solids of from about 150 to about 1000, preferablyfrom about 156 to about 700. Usually the resin mixture will consist ofdi- or polyepoxide resins. The most commonly used di- or polyepoxideresins are those based on the diglycidyl ether of bisphenol-A, thediglycidyl ether of bisphenol F and the diglycidyl ether of an epoxynovolac derived from a phenol and formaldehyde with an averagefunctionality of about 2 to 4. They are well known in the industry, anddescribed in Y. Tanaka, "Synthesis and Characteristics of Epoxides", inC. A. May, ed., Epoxy Resins Chemistry and Technology (Marcel Dekker,1988). This reference also describes many other epoxy resins that whileless commonly encountered and usually more expensive than the diglycidylether of bisphenol-A and the diglycidyl ether of bisphenol F, would alsobe of use in this invention.

The epoxy resin mixture may be modified with a portion of monofunctionalepoxides, commonly referred to as diluents or reactive diluents.Examples include monoepoxides such as styrene oxide, cyclohexene oxide,ethylene oxide, propylene oxide, butylene oxide, and the glycidyl ethersof phenol, the cresols, tert-butylphenol and other alkyl phenols,butanol, 2-ethylhexanol, and mixtures of monofunctional alcoholscontaining from about 8 to about 18 carbon atoms and the like. They alsoinclude some diepoxides based on low molecular weight diols such asethylene glycol, propylene glycol, butylene glycol, neopentyl glycol,1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, and the like.

The epoxy resin may be used as is, it may be dissolved in an appropriatesolvent, or it may be employed as an already formed emulsion in water orwater/cosolvent blend. It will be recognized by those skilled in the artthat the use of solvent or a water/cosolvent blend may be required withsolid epoxy resins or extremely viscous liquid epoxy resins. The ratioof epoxy groups in the epoxy resin to active amine hydrogens in thehardener can vary from about 0.5 to about 2, and will depend on thenature of the epoxy resin employed and the properties necessary to meeta certain market requirement. With liquid resin, the preferred range isabout 0.9 to 1.3, and with solid resin about 1.2 to 1.6.

Normally, coatings according to this invention will consist of at leasttwo components, one of which contains the epoxy resin, and the other thecuring agent. It will usually be advantageous to include one or moreorganic solvents in one or both components of the coating. The solventsare employed to, for example, reduce the viscosity of the individual orcombined components, to reduce the surface tension of the formulation,to aid in coalescence of the ingredients for optimum film formation, toincrease pot life, and to increase the stability of one or bothcomponents. Particularly useful solvents are the lower molecular weightglycol ethers such as ethylene glycol monopropyl ether, ethylene glycolmonobutyl ether, ethylene glycol monoethyl ether, propylene glycolmonomethyl ether, propylene glycol monoethyl ether, diethylene glycolmonobutyl ether, and the like. Other useful solvents include thearomatic solvents such as xylene and aromatic solvent blends such asAromatic 100, ketones such as methyl ethyl ketone, methyl isobutylketone, esters such as butyl acetate, and alcohols such as isopropylalcohol and butanol. The preferred solvent is ethylene glycol monopropylether (EP).

It will frequently be advantageous to include plasticizers such asbenzyl alcohol, phenol, tert-butylphenol, nonylphenol, octylphenol, andthe like in one or both of the components. Plasticizers reduce the glasstransition temperature of the composition and therefore allow the amineand epoxide to achieve a higher degree of reaction than might otherwisebe possible. Accelerators for the epoxy/amine reaction may be employedin the formulation. Useful accelerators are well known to those skilledin the art and include acids such as salicylic acid, various phenols,various carboxylic acids, and various sulfonic acids, and tertiaryamines such as tris-(dimethylaminomethyl)phenol.

The coating formulation may also include pigments and mixtures ofpigments. The pigments may be ground into the epoxy resin, the hardener,or both. They may also be incorporated with the use of a pigmentgrinding aid or pigment dispersant, which may be used in combinationwith the epoxy resin or the hardener, or may be used alone. The use ofpigment dispersants is well known to those skilled in the art of coatingformulation.

Other additives may also be included in the coatings formulation. Suchadditives include defoamers, surfactants, slip and mar aids, rheologymodifiers, flow aids, adhesion promoters, light and heat stabilizers,corrosion inhibitors, and the like.

EXAMPLE 1

To a 1000 mL 4NRB flask equipped with a mechanical stirrer, heatingmantle, Dean-Stark trap, condenser, and thermocouple was placed 145.5 gof Empol 1018 dimer fatty acid (0.249 mole). After raising thetemperature to 100° C., 150 g of Jeffamine M1000 amine (available fromthe Huntsman Corp., 0.1245 eq 1° amine, 25.2% of composition based onsolids) was added in one portion. According to the manufacturer, theJeffamine M1000 amine had a 1° amine content of 0.83 meq/g, and a totalamine content of 0.85 meq/g. This corresponds to a number averagemolecular weight of about 1200. The ratio of moles of diacid toequivalents of amine in the reaction is 2:1, assuming the dimer acid tobe on average difunctional. A sub-surface nitrogen sparge was started,and the temperature was raised to 250° C. The temperature was held at250° for 2.5 hr., then cooled to 100° C. During the course of the aboveprocedures, 18 g of material were removed from the reaction mixture forvarious analyses. To the mixture was then added 280.6 g (2.47 eq amine)of a mixture of methylene bridged poly(cyclohexyl-aromatic)amines(MBPCAA, amine eq wt =55). With a sub-surface nitrogen sparge, themixture was heated to 200° for 1.25 hr., then the temperature was raisedto 250° for 1 hour. After raising the temperature to 250°, the mixturebecame quite foamy for a short period of time as water was purged fromthe mixture. At the completion of these treatments all absorptions dueto carboxylic acid and carboxylate anion were absent from the IRspectrum. The reaction mixture was allowed to cool to 100°, and 94.1 gof EP was added through an addition funnel. The calculated aminehydrogen equivalent weight was 149.0 (124.9 based on solids), theviscosity (Brookfield CP52 spindle, 0.3 rpm, 60° C.) was 369 cP, and the% NV (1 hr., 110° C) was 83.8%. On a 100% solids basis the compositionis 25.2% Jeffamine M1000 amine, 24.5% Empol 1018 dimer fatty acid, and50.3% MBPCAA.

EXAMPLE 2

A blend that on a solids basis consists of 20.0% Jeffamine M1000 amine,19.4% Empol 1018 dimer fatty acid, and 60.6% MBPCAA was prepared bymixing 79.37 g of the curing agent of Example 1, 3.34 g of Ektasolve EP,and 17.29 g of MBPCAA. The viscosity of the mixture (Brookfield CP52spindle, 0.3 rpm, 60° C.) was 430 cP, the calculated % NV was 83.8%, andthe calculated amine hydrogen equivalent weight was 118.0 (98.9 based onsolids).

EXAMPLE 3

To a 1000 mL 4NRB flask equipped with a mechanical stirrer, heatingmantle, short path condenser, sub-surface nitrogen sparge andthermocouple was placed 255 g of Empo11018 dimer fatty acid (0.437mole). and 90 g of Jeffamine M1000 amine (0.075 eq 1° amine, 15.0% ofcomposition based on solids). The ratio of moles of diacid toequivalents of amine in the reaction is 5.8:1, assuming the dimer acidto be on average difunctional. A sub-surface nitrogen sparge wasstarted, and the temperature was raised to 250° C. As the temperatureapproached 250°, considerable bubbling occurred for a short period oftime as water was purged from the system. The temperature was held at250° for 1 hr., then cooled to about 80° C. To the mixture was thenadded 256 g (2.25 eq of amine) of MBPCAA. With a sub-surface nitrogensparge, the mixture was heated to 250° for 2 hr., and again the mixturebecame quite foamy for a short period of time as water was purged fromthe mixture. The reaction mixture was allowed to cool to 100°, and 146.3g of EP was added through an addition funnel. The calculated aminehydrogen equivalent weight was 248.6 (197.4 based on solids), theviscosity (Brookfield CP52 spindle, 0.3 rpm, 60° C.) was 4577 cP and the% solids (1 hr., 110° C.) was 79.4%. On a solids basis, the compositionis 15% Jeffamine M1000 amine, 42.5% Empol 1018 dimer fatty acid, and42.5% MBPCAA.

EXAMPLE 4

To a 1000 mL 4NRB flask equipped with a mechanical stirrer, heatingmantle, short path condenser, sub-surface nitrogen sparge andthermocouple was placed 225 g of Empol 1018 dimer fatty acid (0.386mole). and 150 g of Jeffamine M1000 amine (0.125 eq 1° amine, 24.8% ofcomposition based on solids). The ratio of moles of diacid toequivalents of amine in the reaction is 3.08:1, assuming the dimer acidto be on average difunctional. A sub-surface nitrogen sparge wasstarted, and the temperature was raised to 250° C. As the temperatureapproached 250°, considerable bubbling occurred for a short period oftime as water was purged from the system. The temperature was held at250° for 1 hr., then cooled to about 80° C. To the mixture was thenadded 228.8 g (2.01 eq amine) of MBPCAA. With a sub-surface nitrogensparge, the mixture was heated to 250° for 2 hr., and again the mixturebecame quite foamy for a short period of time as water was purged fromthe mixture. The reaction mixture was allowed to cool to 100° , and146.5 g of EP was added through an addition funnel. The calculated aminehydrogen equivalent weight was 254.9 (205.7 based on solids), theviscosity (Brookfield CP52 spindle, 0.3 rpm, 60° C.) was 1443 cP, andthe % solids (1 hr., 110° C.) was 80.7%. The final composition based onsolids was 24.8% Jeffamine M1000 amine, 37.3% Empol 1018 dimer fattyacid, and 37.9% MBPCAA.

EXAMPLE 5

To a 1000 mL 4NRB flask equipped with a mechanical stirrer, heatingmantle, short path condenser, sub-surface nitrogen sparge andthermocouple was placed 187.5 g of Empol 1018 dimer fatty acid (0.321mole). and 150 g of Jeffamine M1000 amine (0.125 eq 1° amine, 25.2% ofcomposition based on solids). The ratio of moles of diacid toequivalents of amine in the reaction is 2.57:1, assuming the dimer acidto be on average difunctional. A sub-surface nitrogen sparge wasstarted, and the temperature was raised to 250° C. As the temperatureapproached 250°, considerable bubbling occurred for a short period oftime as water was purged from the system. The temperature was held at250° for 1 hr., then cooled to about 80° C. To the mixture was thenadded 258.5 g (2.27 eq amine) of MBPCAA. With a sub-surface nitrogensparge, the mixture was heated to 250° for 2 hr., and again the mixturebecame quite foamy for a short period of time as water was purged fromthe mixture. The reaction mixture was allowed to cool to 100°, and 147.1g of EP was added through an addition funnel. The calculated aminehydrogen equivalent weight was 198.9 (159.5 based on solids), theviscosity (Brookfield CP52 spindle, 0.3 rpm, 60° C.) was 676 cP, and the% solids (1 hr., 110° C.) was 80.2%. On a solids basis the compositionwas 25.2% Jeffamine M1000 amine, 31.5% Empol 1018 dimer fatty acid, and43.4% MBPCAA.

EXAMPLES 6-11

The A side (containing the epoxy resin) and B side (containing thehardener) clearcoat formulations of Table 1 were prepared. All of theseformulations are calculated to be either 65% or 55% solids by weight,including the nonylphenol plasticizer as solids, and have a 200 g totalbatch weight. The level of EP is that which is calculated to yield theVOC indicated. The formulations were allowed to equilibrate for at least15 hours. The mixtures were then combined by adding the B side to the Aside and thoroughly mixing. After standing for a 30 min. inductionperiod, the mixtures were reduced in viscosity by the addition ofdeionized water to a spray viscosity of about 25 sec. in a Zahn #2 cup.Coatings were prepared by drawdown using a #50 wire wound rod (Paul N.Gardner Co.) on 3"×6" polished cold rolled steel (Q Panel Co.) or 3"×6"16 ga. grit blasted hot rolled steel with a 2 mil profile (Custom LabSpecialties Co.). Pot lives were determined by the time necessary toobtain about a 10% drop in gloss of coatings applied every half hour tocold rolled steel, by the time required for the viscosity to double, orby the time necessary for the composition to become phase separated tothe extent that an accurate measure of viscosity could not be taken inthe Zahn cup, whichever was a shorter time. The indicated pot lives donot include the 30 minute induction time as part of the pot life.Humidity resistance was measured using a Cleveland Condensing Humiditytest (ASTM D 4585) operating with a cycle of 10 hr. wet at 40° C./2 hr.dry at 45° C. Panels were rated for visual estimation of the degree ofrusting (ASTM D 610) and blistering (ASTM D 714). Performance data iscollected in Table 2.

                  TABLE 1                                                         ______________________________________                                                    Example                                                                       6    7      8      9    10   11                                   ______________________________________                                        A Side                                                                        Epoxy Resin,  72.5   78.42  72.5 58.61                                                                              58.17                                                                              61.00                              EEW = 190                                                                     Nonylphenol   16.93  16.92  16.93                                                                              16.93                                                                              16.93                                                                              14.32                              Aromatic 100  1.45   1.57   1.45 1.16 1.16 1.22                               B Side                                                                        Hardener of Ex. 1                                                                           48.14         48.14                                             Hardener of Ex. 2    41.03                                                    Hardener of Ex. 4                67.72                                                                              67.74                                   Hardener of Ex. 5                          42.95                              DI Water      49.99  49.95  49.88                                                                              43.62                                                                              36.65                                                                              61.92                              EP            10.84  11.84  10.84                                                                              12.21                                                                              19.14                                                                              18.36                              Dee-Fo P14    0.25   0.25   1.25 0.25 0.25 0.25                               Concentrate                                                                   DI Water to Reduce                                                                          36.26  10.55  28.26                                                                              57.08                                                                              69.10                                                                              4.7                                to 25 sec Viscosity                                                           Calculated                                                                    Constants                                                                     Plasticizer on                                                                              15     15     15   15   15   15                                 Solids                                                                        Eq Epoxy /Eq. N-H                                                                           1.18   1.19   1.18 1.15 1.15 1.49                               VOC (lb/gal)  1.20   1.20   1.20 1.50 1.80 1.80                               % Weight Solids                                                                             65     65     65   65   65   55                                 Before Let-Down to                                                            Spray Viscosity                                                               ______________________________________                                    

Examples 1, 3, 4, and 5 show that as the ratio of moles of diacid toequivalents of amine is increased in the first step, the viscosity ofthe curing agent and the amine hydrogen equivalent weight increases.Both result in an increase in VOC and a decrease in application solids,as shown in Tables 1 and 2. Comparison of Examples 6 and 7 shows that bydecreasing the level of Jeffamine M1000 from 25% to 20%, the applicationsolids increases and the humidity resistance of the coating improves,while the thin film set time decreases without affecting the pot life.Experiment 8 shows that by increasing the level of defoamer employedwith the hardener of Example 1, the application solids is improved alongwith the humidity resistance. While the overall balance of propertiesfor most applications is superior in Example 7 which is based on thehardener of Example 2, the hardeners of Example 4 and particularlyExample 5 are superior in those applications that require a high degreeof film flexibility and where a relatively slow cure and a higher VOCcontent can be tolerated, as shown in Examples 9-11. The curing agent ofExample 5 is preferred over that of Example 4 because of its lowerviscosity and better humidity resistance.

                                      TABLE 2                                     __________________________________________________________________________               Example                                                                       6   7   8   9    10   11                                           __________________________________________________________________________    Dry-to-touch (hr.)                                                                       3.75                                                                              4.0 3.75                                                                              6.5  5.0  7.0                                          Thin Film Set (hr.)                                                                      11.25                                                                             9.5 13.0                                                                              16.5 18.25                                                                              12.25                                        Pendulum Hardness                                                                        65  67  62  28   32   20                                           (Rocks, 1 week cure)                                                          % Rust (ASTM                                                                             1.0 0.3 0.3 10   10   0.5                                          D610)                                                                         Blistering (ASTM                                                                         10  10  10  10   10   10                                           D714)                                                                         Pot Life (hr.)                                                                           5.0 5.0 4.5 1.5  5.5  4.5                                          Cause of End of Pot                                                                      PS  PS  PS  V    PS   PS                                           Life                                                                          Reverse Impact (in-                                                                      4   8   16  >160 >160 >160                                         lb)                                                                           Forward Impact (in-                                                                      56  44  128 >160 >160 >160                                         lb)                                                                           Initial 60° Gloss                                                                 107 109 110 118  116  115                                          First Stage                                                                              2.0 2.0 2.0 3.08 3.08 2.57                                         Mole Acid:Eq Amine                                                            __________________________________________________________________________     PS -- Phase Separation                                                        GL -- Gloss Loss                                                              V -- Viscosity Increase                                                  

COMPARATIVE EXAMPLES 12-14

The formulations of Table 3 were prepared and tested according to theprotocol of Examples 6-11. Anquamine 360 curing agent is a water-borneamidoamine commercially available from Air Products and Chemicals, Inc.with a % NV of 50 and an AHEW of 280. Anquamine 401 curing agent is acommercially available water-borne polyamine adduct curing agent fromAir Products and Chemicals, Inc., with a % NV of 70 and AHEW of 200.EPI-REZ Resin 5522-WY-55 is a solid epoxy dispersion with an equivalentweight of 625 based on solids and a % NV of 55 and is commerciallyavailable from the Shell Chemical Co. EPI-CURE Curing Agent 8290-Y-60 isa water-borne polyamine adduct curing agent commercially available fromthe Shell Chemical Co. with a % NV of 60 and an equivalent weight of163. The EPI-CURE 8290 and EPI-REZ 5522 were employed at a 15:85 weightratio, which is recommended by the manufacturer to improve water andcorrosion resistance and increase pot life relative to thestoichiometric ratio. Performance data is collected in Table 4.

                  TABLE 3                                                         ______________________________________                                                       Comparative Example                                                           12      13     14                                              ______________________________________                                        A Side                                                                        Epoxy Resin, EEW = 190                                                                         53.87     63.02                                              Epi-Rez WJ-5522                   138.15                                      Benzyl Alcohol   9.78      11.44                                              EP               8.87      8.39   8.49                                        Aromatic 100     1.28      1.5                                                B Side                                                                        Anquamide 360    66.16                                                        Anquamine 401              55.28                                              Epi-Cure 8290-Y-60                22.41                                       DI Water         49.62     50.22  30.44                                       EP               10.16     9.89                                               Dee-Fo P14 Concentrate                                                                         0.25      0.25   0.25                                        DI Water to Reduce to                                                                          45.16     43.13  39.41                                       25 sec Viscosity                                                              Calculated Constants                                                          % Plasticizer on Solids                                                                        11.25     11.25  0                                           Eq Epoxy/Eq N-H  1.2       1.2    1.48                                        VOC (lb/gal)     1.20      1.20   2.18                                        ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                                       Example                                                                       12     13      14                                              ______________________________________                                        Dry-to-touch (hr.)                                                                             3        3.25    1.75                                        Thin Film Set (hr.)                                                                            3        2.25    1.75                                        Pendulum Hardness                                                                              92       115     54                                          (Rocks, 1 week cure)                                                          % Rust (ASTM D610)                                                                             0.1      3       1                                           Blistering (ASTM D714)                                                                         6M       8D      10                                          Pot Life (hr.)   0.5      <0.5    4.5                                         Cause of End of Pot Life                                                                       V        V, GL   GL                                          Reverse Impact (in-lb)                                                                         <4       4       20                                          Forward Impact (in-lb)                                                                         20       52      112                                         Initial 60° Gloss                                                                       75       107     109                                         ______________________________________                                    

It is clear by comparison of Tables 2 and 4 that compositions of thepresent invention offer superior pot life and humidity resistancecompared to other curing agents employed as emulsifiers for liquid epoxyresin. Compared to the solid resin dispersion and curing agentcomposition, the present invention offers better humidity resistance andcomparable pot life along with much lower VOC and higher applicationsolids.

STATEMENT OF INDUSTRIAL APPLICATION

The present invention provides water dispersible curing agents forliquid and solid epoxy resin coating compositions.

I claim:
 1. A coating composition comprising a polyepoxide resin and anepoxy hardener composition comprising the reaction product of (A) apoly(alkylene oxide) mono- or diamine having a number average molecularweight (Mn) of 500 to 3000 and (B) a polycarboxylic acid in a ratio ofmoles of polycarboxylic acid to equivalents of amine of about 1:1 to 6:1to yield an intermediate (C) which is reacted with (D) a polyamine whichis selected from the group consisting of aliphatic diamines andpolyamines, araliphatic diamines and polyamines, aromatic diamines andpolyamines, cycloaliphatic diamines and polyamines, heterocyclicdiamines and polyamines, and mixtures thereof, the amount of thepoly(alkylene oxide) monoamine or diamine used to produce intermediate(C) being sufficient to provide a stable solution or emulsion of theepoxy hardener composition in an aqueous medium.
 2. The coatingcomposition of claim 1 in which the amount of the poly(alkylene oxide)monoamine or diamine used to produce intermediate (C) comprises 15 to 40wt % of the epoxy hardener composition.
 3. The coating composition ofclaim 1 in which the amount of the poly(alkylene oxide) monoamine ordiamine used to produce intermediate (C) comprises 18 to 25 wt % of theepoxy hardener composition.
 4. The coating composition of claim 1 inwhich the ratio of moles of polycarboxylic acid to equivalents of aminein the production of intermediate (C) ranges from 1.3:1 to 2.6:1.
 5. Thecoating composition of claim 2 in which the ratio of moles ofpolycarboxylic acid to equivalents of amine in the production ofintermediate (C) ranges from 1.3:1 to 2.6:1.
 6. The coating compositionof claim 1 in which component (A) is a poly(alkylene oxide) monoamine.7. The coating composition of claim 1 in which the polycarboxylic acidis a dicarboxylic acid containing 3 to 12 carbon atoms.
 8. The coatingcomposition of claim 1 in which the polycarboxylic acid is a dimer fattyacid.
 9. The coating composition of claim 1 in which polyamine (D) isselected from the group consisting of polyethylene amines,1,2-propylenediamine, 1,3-propylene-diamine, 1,4-butanediamine,1,5-pentanediamine, 1,3-pentanediamine, 1,6-hexanediamine,3,3,5-trimethyl-1,6-hexanediamine, 3,5,5-trimethylol ,6-hexanediamine,2-methyl-1,5-pentanediamine, bis-(3-aminopropyl)amine,N,N'-bis-(3-aminopropyl)-1,2-ethanediamine,N-(3-aminopropyl)-1,2-ethanediamine, 1,2-diaminocyclohexane,1,3-diaminocyclohexane, 1,4-diaminocyclohexane, aminoethylpiperazine,meta-xylylenediamine, phenylenediamine, 4,4'-diaminodiphenylmethane,toluenediamine, isophoronediamine,3,3'-dimethyl-4,4'-diaminodicyclohexylmethane,4,4'-diaminodicyclohexylmethane, 2,4'-diaminodicyclohexyl methane, themixture of methylene bridged poly(cyclohexyl-aromatic)amines,polyaminoamides, and mixtures thereof.
 10. The coating composition ofclaim 1 in which polyamine (D) is 4,4'-diaminodicyclohexyl methane. 11.The coating composition of claim 1 in which polyamine (D) is a mixtureof methylene bridged poly(cyclohexyl-aromatic)amines.
 12. A coatingcomposition comprising a polyepoxide resin and an epoxy hardenercomposition comprising the reaction product of (A) a poly(alkyleneoxide) mono- or diamine having a number average molecular weight (Mn) of500 to 3000 and (B) a dicarboxylic acid in a ratio of moles ofdicarboxylic acid to equivalents of amine of about 1.3:1 to 6:1 to yieldan intermediate (C) which is reacted with (D) a polyamine which isselected from the group consisting of aliphatic diamines and polyamines,araliphatic diamines and polyamines, aromatic diamines and polyamines,cycloaliphatic diamines and polyamines, heterocyclic diamines andpolyamines and mixtures thereof, the amount of the poly(alkylene oxide)monoamine or diamine used to produce intermediate (C) being 15 to 40 wt% of the epoxy hardener composition.
 13. The coating composition ofclaim 12 in which the amount of the poly(alkylene oxide) monoamine ordiamine used to produce intermediate (C) comprises 18 to 25 wt % of theepoxy hardener composition.
 14. The coating composition of claim 12 inwhich the ratio of moles of dicarboxylic acid to equivalents of amine inthe production of intermediate (C) ranges from 1.3:1 to 2.6:1.
 15. Thecoating composition of claim 12 in which component (A) is apoly(alkylene oxide) monoamine.
 16. The coating composition of claim 12in which the dicarboxylic acid contains 3 to 12 carbons atoms.
 17. Thecoating composition of claim 12 in which the dicarboxylic acid is adimer fatty acid.
 18. The coating composition of claim 12 in whichpolyamine (D) is selected from the group consisting of polyethyleneamines, 1,2-propylenediamine, 1,3-propylene-diamine, 1,4-butanediamine,1,5-pentanediamine, 1,3-pentanediamine, 1,6-hexanediamine,3,3,5-trimethyl-1,6-hexanediamine, 3,5,5-trimethyl-1,6-hexanediamine,2-methyl-1,5-pentanediamine, bis-(3-aminopropyl)amine,N,N'-bis-(3-aminopropyl)-1,2-ethanediamine,N-(3-aminopropyl)-1,2-ethanediamine, 1,2-diaminocyclohexane,1,3-diaminocyclohexane, 1,4-diaminocyclohexane, aminoethylpiperazine,meta-xylylenediamine, phenylenediamine, 4,4'-diaminodiphenylmethane,toluenediamine, isophoronediamine,3,3'-dimethyl-4,4'-diaminodicyclohexylmethane,4,4'-diaminodicyclohexylmethane, 2,4'-diaminodicyclohexyl methane, themixture of methylene bridged poly(cyclohexyl-aromatic)amines,polyaminoamides, and mixtures thereof.
 19. The coating composition ofclaim 14 in which polyamine (D) is 4,4'-diaminodicyclohexyl methane. 20.The coating composition of claim 14 in which polyamine (D) is a mixtureof methylene bridged poly(cyclohexyl-aromatic)amines.
 21. A coatingcomposition comprising a polyepoxide resin and an epoxy hardenercomposition comprising the reaction product of (A) a poly(alkyleneoxide) monoamine having a number average molecular weight (Mn) of 800 to1500 and (B) a dicarboxylic acid in a ratio of moles of dicarboxylicacid to equivalents of amine of about 1.3:1 to 2.6:1 to yield anintermediate (C) which is reacted with (D) a polyamine, the amount ofthe poly(alkylene oxide) monoamine used to produce intermediate (C)being 18 to 25 wt % of the epoxy hardener composition.
 22. The coatingcomposition of claim 21 in which polyamine (D) is4,4'-diaminodicyclohexyl methane.
 23. The coating composition of claim21 in which polyamine (D) is a mixture of methylene bridgedpoly(cyclohexyl-aromatic)amines.
 24. The coating composition of claim 21in which the poly(alkylene oxide) monoamine is a monoamine terminatedblock copolymer of propylene oxide and ethylene oxide having an Mn ofabout 1200 based on its amine titer.
 25. The coating composition ofclaim 21 in which the dicarboxylic acid (B) is selected from the groupconsisting of a dicarboxylic acid containing 3 to 12 carbons atoms and adimer fatty acid.
 26. A coating composition comprising a polyepoxideresin and an epoxy hardener composition comprising the reaction productof (A) a poly(alkylene oxide) monoamine having a number averagemolecular weight (Mn) of 500 to 3000 and (B) a polycarboxylic acid in aratio of moles of polycarboxylic acid to equivalents of monoamine ofabout 1:1 to 6:1 to yield an intermediate (C) which is reacted with (D)a polyamine, the amount of the poly(alkylene oxide) monoamine used toproduce intermediate (C) being sufficient to provide a stable solutionor emulsion of the epoxy hardener composition in an aqueous medium.